How much coffee powder does 1shot espresso need? Suggestion on extraction parameters of single concentrated powder bowl coffee

Usually we call a single espresso "1 shot"! Shot is actually a unit of wine measurement. 1 shot equals 1 ounce, or about 30ml. The standard amount of coffee powder for 1 shot espresso is 9-11g. This parameter is rarely used these days. The reason for this comes from a single concentrated powder bowl.

-single concentrated powder bowl-double concentrated powder bowl, I believe those who have come into contact with the semi-automatic coffee machine will be very familiar with it. The volume of the powder bowl has a columnar structure, and the extracted pressed powder is also a regular piece of "round almond cake". And the single concentrated powder bowl is in the shape of inverted cone. Roughly two-tier structure, the upper half is the same caliber as the double powder bowl. However, the powder content of a single powder bowl is half that of a double powder bowl, so a narrowed design has been made in the lower half of the bowl, so that the surface caliber and the maximum thickness of the powder layer can be kept the same.

However, in the Qianjie extraction experiment, a single powder bowl is not as simple as a double powder bowl. In front of the street, a double powder bowl was used to extract 40g coffee liquid on the basis of 20g powder, which took 27 seconds, the measured concentration was 10.48%, and the extraction rate was 21.72%. Using a single powder bowl, taking 10g powder as the basis, 20g coffee liquid was extracted, the flow rate was relatively fast, it took 22 seconds, the measured concentration was 8.83%, and the extraction rate was 18.38%. There is a big difference between the two.

If you want to make the product of a single powder bowl close to a double powder bowl, you can only fine-grind or increase the amount of powder. Grinding products is not realistic for coffee shops, increasing the amount of powder will increase the cost and uncertainty. Qianjie test, the need to increase to 12.5g powder, the concentration will be close to the data of the double powder bowl.

-Why is it so different?-it all starts with the structure. The structure of the double concentrated powder bowl is straight and cylindrical, which makes the force of each part is uniform and the extraction is more uniform, whether it is pressing powder or pressurized extraction.

In order to keep the diameter of the powder bowl uniform (so that it can fit the cooking head), and at the same time ensure the thickness of the powder layer, sacrifice the bottom structure, so that whether it is pressing powder or pressure extraction, the pressure around is always higher than the pressure at the same level center. When pressing powder, the four sides will be denser than the center, and during extraction, the water in the upper half and the center will permeate faster than around, but the water around the lower half will converge to the center, resulting in uneven extraction and serious channel effect.

For such "chicken rib" utensils, although single powder bowls and double powder bowls are still distributed when buying a coffee maker, most of the time, single powder bowls are sealed directly back into the box. Now more and more espresso extracted by double powder bowl is regarded as one part concentrated, and the ratio of powder to liquid also tends to 1:2.